text: #ifndef CELL_INCLUDE
  #define CELL_INCLUDE
  
  enum cell_type {
    UNVISITED,
    VISITED,
    FREE,
    BLOCK
  };
  
  // cell is a single point in the grid environment
  class cell {
    public:
      int row;
      int col;
  
      cell();
      cell(int r, int c);
      double euclidean_distance(cell& other);
      bool is_equal(cell& other);
  };
  
  #endif